UPS Input Circuit Power Factor Correction via PWM Frequency Control
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Solution Overview
Problem
Rectifiers and non-linear loads in power distribution systems distort current, lower power factor, and generate harmonic noise, leading to inefficiencies and increased power supply costs, which affect the commercial viability of UPS systems.
Innovation Solution
An uninterruptable power supply (UPS) system with an input circuit that includes a transistor, inductor, and controller, which uses pulse width modulation to adjust switching frequency and provide power factor correction, controlling operating frequencies and total harmonic distortion through a method involving current sensors and digital signal processing to generate control signals for the transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If rectifiers and non-linear loads are used in power distribution systems, then power conversion functionality is provided, but current distortion and harmonic noise increase, lowering power factor and reducing system efficiency
Solution Approach 1:
The patent applies active power factor correction technology that converts the harmful effect of non-linear loads into beneficial functionality by using control circuits to actively manage and correct the distorted current waveforms, transforming the problem of harmonic distortion into an opportunity for improved power quality and efficiency
2Reliability
If rectifiers operate inefficiently, then power supply costs increase, but the ability to provide uninterrupted power is maintained
Solution Approach 1:
The patent implements feedback control mechanisms where control circuits continuously monitor system performance parameters and adjust operating conditions in real-time to optimize efficiency while maintaining uninterrupted power supply reliability, preventing energy losses through active management of power conversion processes
3Productivity
If switching frequency is increased to improve power factor correction, then efficiency improves, but audible noise increases during heavy load conditions
Solution Approach 1:
The patent employs dynamic switching frequency adjustment where the switching frequency is varied based on operating conditions and load requirements, allowing the system to optimize power factor correction efficiency while keeping switching frequencies above the human audible range during heavy load conditions, thereby eliminating audible noise through adaptive frequency control
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves improved power factor correction, reduces total harmonic distortion, and optimizes switching frequencies to enhance efficiency and reduce audible noise, thereby increasing the commercial viability of UPS systems.
Implementation Method 1
uses pulse width modulation to adjust switching frequency and provide power factor correction
Data Source
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AI summary
Systems and methods for operating an uninterruptable power supply are provided. The uninterruptable power supply may include a rectifier that has a transistor and an inductor. The uninterruptable power supply may also include a controller. A current sensor can be configured to detect inductor current and to provide a detected inductor current value to the controller to generate a current error value based and to generate a pulse width modulation control signal based in part on the current error value. The controller can apply the pulse width modulation control signal to the transistor to adjust a switching frequency of the transistor.